SparkFun Forums

[PhilipD]

Hi all,

I am new at this and I would like your opinion on my plans to put two LED lights on my welding helmet. Because I often weld in dark areas (boxes, pipes, under tables, etc) I would like to put a battery powered LED on my helmet so I can see the welding rod or the TIG gug. This is what I have come up with. Let me know what you think.

9v battery with holder
thumb operated on/off switch to turn the lights on and off
2 5mm super bright white LEDs with holders
1 110 OHM resistor

I will come out of the positive side of the battery and go into the on/off switch and then into the 110 ohm resistor. Then into the positive side of one LED and out the negative side into the positive side of the other. Next come out of the negative side of the second LED and into the negative side of the battery.

Please provide any advice or suggestions you may have.

Thanks
Philip

[DanV]

You are going to need to know what the current requirements are for the LED's.
Then you can refer to this site for resistor calculation:
http://www.hobby-hour.com/electronics/ledcalc.php

[PhilipD]

Thank you DanV. The site you linked to is where I got the value for the 110 ohm resistor.